As a synthesis method of DME (dimethyl ether), for example, a method of producing DME and water due to dehydration reaction of ethanol is conventionally known.
In this synthesis method, the produced water and the produced DME increase as the reaction proceeds, and apparent reaction is ended when equilibrium composition is achieved at a reaction temperature. In order to increase the production amount of DME per the amount of the same crude methanol, in a conventional technique, after a gas from an exit of a reactor is cooled, the cooled gas is gas-liquid separated, and DME is recovered as a gas phase while produced water and unreacted methanol are recovered as a liquid phase. Furthermore, the recovered liquid phase is introduced into a distillation tower so that the liquid phase is separated into water and methanol by distillation, and the separated water is discharged outside the system while the separated methanol is circulated into the reactor.
Furthermore, for example, as a synthesis method of terephthalic acid, a method of producing terephthalic acid by paraxylene being subjected to an air oxidation reaction by using an oxidation catalyst under the existence of a solvent of aliphatic carboxylic acid such as acetic acid is common. In this synthesis method, as a result of producing water along with the oxidation reaction, in a conventional technique, an oxidized exhaust gas from an oxidation reactor or a condensate liquid of the oxidized exhaust gas and other solvent containing water generated in the system are introduced into a distillation tower so as to be distilled, and the reaction solvent is recovered by removing oxidized product water.
FIG. 4 is a sectional view showing a part of a separation membrane 110 for a conventional separation device.
In the separation device shown in FIG. 4, a fluid is introduced from below into a first chamber 111 in the cylindrical separation membrane 110 capable of allowing water to pass through in vapor form, and as the fluid rises, the water content in the fluid is moved into a depressurized second chamber 121 that accommodates the separation membrane 110, and the dehydrated fluid is discharged from the top of the first chamber 111.
In FIG. 4, the separation membrane 110 is held between the top part and the bottom part of the second chamber 121 via O-rings 130T and 130B.
Also, in the above-described dehydrating membrane separation device, in addition to the O-rings shown in FIG. 4, sealing means, for example, as shown in FIGS. 5(A) to 5(D), are provided. In FIGS. 5(A) to 5(D), reference numeral 101 denotes a part connecting with a shell body, and 102 denotes a cylindrical body forming the separation membrane.
In FIG. 5(A), a seal is provided by putting a grand packing 103 and pressing it by using a pressing member 110. In FIG. 5(B), a seal is provided by an O-ring 105 installed in an O-ring case 111. In FIG. 5(C), a seal is provided by installing a U-packing 104. In FIG. 5(D), a seal is provided by installing a T-ring 106.
One usage example of a separation membrane has been proposed in Patent Literature 1 (Japanese Unexamined Patent Application Publication No. 2004-89882) and Patent Literature 2 (Japanese Unexamined Patent Application Publication No. 2004-89883). These Publications disclose a technique in which a fluid is caused to flow in a membrane separation device having a separation membrane that allows water to permeate and extends in the vertical direction.